Figure 6.5. Ionotropic receptor. Binding of a neurotransmitter molecule
(triangles) to a specific site on the receptor shifts the shape of the protein and
opens a channel that allows specific ions to pass through.To recap: an ionotropic neurotransmitter receptor protein, or
ligand-gated receptor, is made of protein that spans the lipid-bilayer
cell membrane and has a doughnut-like hole or pore running through
its structure (Fig. 6.5). Such receptor proteins are often composed of
several (generally four or five) protein subunits arranged to form the